The invention relates to an apparatus for reading codes of thermoluminescence detectors, wherein the thermoluminescence detectors are arranged in a disc-like round magazine all at the same distance from the axis of the magazines.
With the official fingering dosimeter system dosimeter probes as they are know from DE 196 43 347.7 with marked TL detectors according to DE 196 43 316.9 are utilized. The identification numbers in the omnidirectional code, which are disposed on the detectors (size 3.1xc3x973.1xc3x971 mm3 or 13.9xc3x971 mm3 must be read for the assignment of the individual calibration factor of each detector in order to determine the dose. This is done with commercially available components such as video cameras with stands and decoders, wherein each detector has to be brought manually in a reading position. For an efficient evaluation in corresponding automatic measuring apparatus, the detectors are placed into round magazines. If detectors were lost during the surveillance period of a month, the magazine locations where the lost detectors would normally be placed, must be left unoccupied for operational reasons, since the evaluation is performed on the basis of dosimeter numbers, no matter whether the respective detectors are present or not. This requires high concentration and attention of the operating personnel. The above reading arrangement offers no possibility to prevent wrong positioning of the detectors on the magazine by the operators and, furthermore, has the disadvantage that, with such an open arrangement for the camera, undesirable light effects to the observation area may result in contrast changes of the code image, whereby the reading accuracy is detrimentally affected. Apparatus, which do not have these disadvantages, are not available commercially.
It is therefore the object of the present invention to provide an apparatus for reading codes of thermoluminescence detectors, which overcome the disadvantages referred to above.
In an apparatus for reading codes of a thermoluminescence detector, a housing including an optical unit is disposed on a base together with a disc-like magazine which is rotatably supported adjacent a housing and provided with an annular array of recesses receiving the thermoluminescence detectors to be examined. The housing has a side opening through which the magazine extends into the housing, in which a light source is disposed for the homogeneous illumination of the thermoluminescence detectors from one side thereof, A CCD camera is disposed in the housing at the other side of the magazine for recording the luminescence generated by the detectors when exposed to the light from the light source for determining the radiation exposure of thermoluminescence detectors.
It is an important advantage of the apparatus according to the invention that it has a relatively small size but provides for optimal reading quality while undesirable lighting effects are eliminated. If furthermore permits only a proper placement of the detectors on the magazine. Also, control by a PC is facilitated.
Below, the invention will be described in greater detail on the basis of the accompanying drawings.